Electronic devices are used for a wide range of applications, including communication, computing and control. Such devices tend to be complex and therefore require extensive testing during design to assure correct performance. In addition, electronic devices often require monitoring and troubleshooting after installation, throughout their working life.
During debugging, testing and/or troubleshooting, a technician may provide the electronic device with a preselected input signal, and monitor a resulting output signal of the device to determine whether the device is operating properly. However, this is not always sufficient, and in some cases it is desired to monitor internal signals of the device at one or more internal points. A register may be used to store such an internal digital value representation, which can then be retrieved for displaying on an external display for viewing by the technician. When it is desired to view an internal analog signal, the analog signal is generally first converted into a digital form by an analog to digital converter (ADC) and only then is it provided to the external display. An ADC capable of operating at high speeds is typically both large and power hungry. Consequently, many high speed devices are produced without offering any possibility to view internal analog signals for debugging purposes.